PREDICTION OF MACROMOLECULAR TRANSPORT THROUGH THE DEFORMABLE POROUS-MEDIA OF AN ARTERY WALL BY PORE THEORY

To determine the transport properties of macromolecules in the media o f an artery wall deformed inhomogeneously by the transmural pressure, we combine a simple mechano-hydraulic model based on a two parameter s train-dependent permeability function, which was developed by Klanchar and Tarbell [1987], with a pore theory. The combined theory allows us to calculate the spatial distributions of porosity, solute partition, pore radius and macromolecular solute concentration in the media and their dependence on the transmural pressure. The predictions from the pore theory are in good agreement with experimental measurements of su crose space, albumin space and albumin concentration profiles in the m edia of rabbit aortas al transmural pressures of 70 and 180 mmHg. The prediction indicates that albumin transport through the aortic media i s dominated by convection rather than diffusion. It is further demonst rated that the transport properties of planar tissue samples, which ar e often used in in vitro experimentals, may be quite different from th ose of intact vessels in their natural cylindrical configuration becau se of the variation in tissue deformation. Using the pore theory we ar e also able to calculate the interstitial shear stress associated with transmural volume flow which may act on the smooth muscle cells resid ing in the media and find it to be on the order of several dyne/cm(2). This level of shear stress will stimulate endothelial cells and may a lso affect smooth muscle cells.